In a conventional synchronizing system, a desired speed signal and a speed signal indicating the actual speed of a master driving unit are fed to a comparing means producing a differential signal by subtracting the actual speed signal from the desired speed signal. The differential signal is fed to the control means controlling the speed of the master unit. The speed control means produces a control signal which is directly supplied to the master unit and which is further supplied to the slave units after adding a supplemental control signal. For generating the supplemental control signal for all slave units a synchronizing controller is provided in which the difference of the actual positional signals of the individual drive units is determined. The actual positional signals of the units each are derived from the actual speed values of the units in an integrating member. The conventional synchronization exhibits relatively large inaccuracies. This is particularly true in synchronizing a plurality of hydraulic cylinders which have inherent dragging errors so that the conventional control results in relatively uneven loads between the master cylinder and the slave cylinders.